Validators
XML Validator
Validate XML syntax and structural well-formedness instantly. Our tool provides detailed error reports with line and column numbers to help you debug XML documents and data feeds effectively.
Validate XML syntax and structural well-formedness instantly. Our tool provides detailed error reports with line and column numbers to help you debug XML documents and data feeds effectively.
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Paste your XML code into the input field at the top of the page.
Click the 'Validate' button to perform a syntax and well-formedness check.
Review any error messages that appear below the editor, which include specific line numbers.
Correct the highlighted issues directly in the editor to resolve syntax errors.
Re-validate the code until you receive a message confirming the XML is well-formed.
Tip
Always use the XML prolog to define the encoding, ensuring your data is interpreted correctly across different systems.
Syntax Verification: Instantly check if your XML follows the standard well-formedness rules.
Precise Diagnostics: Receive clear error messages that specify exactly where the problem occurs.
Line Highlighting: Easily identify structural issues with built-in line and column indicators.
Real-time Feedback: Optimize your development workflow with fast, server-side validation results.
Did You Know?
Unlike HTML, XML is strictly case-sensitive for both element names and attribute names.
Prevent Parser Errors: Ensure your data is readable by XML parsers in any backend environment or programming language.
Ensure Data Integrity: Verify that XML configuration files and data exports are valid before they are used in production.
Speed Up Debugging: Quickly find small mistakes like missing closing tags or case-sensitivity errors that are difficult to spot manually.
Maintain Standards: Confirm that your markup adheres to the fundamental structure required for interoperable data exchange.
Mismatched Tags: Every opening tag must have a corresponding closing tag in the correct nesting order.
Case Sensitivity: Tag names like <Data> and <data> are not interchangeable and will cause validation errors if mismatched.
Unquoted Attributes: All attribute values must be enclosed in single or double quotes to be considered valid XML.
Invalid Reserved Characters: Using symbols like '<' or '&' inside text content without using entity references like < or &.
Best Practice
Wrap complex text data in CDATA tags to avoid escaping multiple special characters individually.
Include the XML Prolog: Always start your files with a declaration such as <?xml version="1.0" encoding="UTF-8"?>.
One Root Element: Ensure your entire document is contained within a single parent element to meet well-formedness standards.
Validate After Edits: Always run a validation check after manual code modifications to ensure no syntax errors were introduced.
Use CDATA for Blobs: For large blocks of text containing special characters, use <![CDATA[...]]> sections to avoid manual escaping.
Q: What does it mean for XML to be 'well-formed'? A: A well-formed XML document follows the basic syntactic rules, such as correct nesting and having a single root element.
Q: Why does my XML fail validation if I use an ampersand? A: The '&' character is reserved for entities; you must replace it with & for the document to be valid.
Q: Can this tool validate against a specific XSD? A: This tool focuses on general XML syntax and well-formedness rather than specific schema definitions or DTDs.
W3C XML Specification - The official technical standard for Extensible Markup Language
MDN Web Docs: XML - A comprehensive guide to understanding and using XML
Wikipedia: Well-formed Document - Background on what constitutes valid XML structure